fix: Add debounced Undo/Redo system to avoid character-by-character history

- Add debounced state updates for title and content (500ms delay)
- Immediate UI updates with delayed history saving
- Prevent one-letter-per-undo issue
- Add cleanup for debounce timers on unmount

mcp-server/node_modules/math-intrinsics/mod.js

@@ -0,0 +1,9 @@
+'use strict';
+
+var $floor = require('./floor');
+
+/** @type {import('./mod')} */
+module.exports = function mod(number, modulo) {
+	var remain = number % modulo;
+	return $floor(remain >= 0 ? remain : remain + modulo);
+};